All the danger of a Penny Farthing, with none of the authenticity. Well in this design of Penny Fakething, there is the advantage that you can dismount forwards, avoiding the 'header' type accidents common with a traditional Penny Farthing.
A modern take on that classic bicycle design.
Step 1: Starting the frame
Select a scrap frame & forks. Cheap 'gaspipe' MTB frames are easy to weld. Remove the forks and assess how it will go together.